The present invention relates to a semiconductor strain gauge, and more particularly to a semiconductor strain gauge having means to carry out zero-point temperature compensation.
Semiconductor strain gauges utilizing a strain gauge diaphragm as the pressure-sensitive elements are known. In the strain gauge of the integral type, a flexible diaphragm is formed in a semiconductor substrate such as silicon. The strain gauge resistance elements or piezoresistive elements are integrally formed on one side of the diaphragm by diffusion process.
The output of the strain-electric signal conversion bridge at the time when the strain is zero exhibits the so-called temperature-dependency in which it changes with a temperature change, on account of the discrepancies of the resistance values and the temperature coefficients of the plurality of gauges constituting the bridge. This temperature-dependency is the zero-point temperature-dependency, and it is the zero-point temperature compensation that reduces and compensates for such temperature-dependency.
For example, U.S. Pat. No. 3,654,545 entitled "SEMICONDUCTOR STRAIN GAUGE AMPLIFIER" (issued on Apr. 4, 1972) discloses a semiconductor strain gauge amplifier which includes a temperature sensor such as thermistor in order to realize such zero-point temperature compensation. Such a compensation circuit, however, is undesirably complicated.